Synostosis of First and Second Ribs: A Case...
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South Asian Anthropologist, 2015, 15(1): 15-17 New Series ©SERIALS 15 Synostosis of First and Second Ribs: A Case Report VIDYA K. SHIVAKUMAR 1 & PRIYA RANGANATH 2 Department of Anatomy, Bangalore Medical College & Research Institute, Bangalore 560002, Karnataka E-mail: [email protected] KEYWORDS: Synostosis. Ribs. First and second. Clinical significance. ABSTRACT: Partial fusion of ribs is a rare anatomical entity. Its incidence is reported to be 0.3% in a study based on radiographs. In an incidental finding in the Dissection Hall, Department of Anatomy, Bangalore Medical College & Research Institute, Bangalore, there was a specimen with partial fusion of left first and second ribs. Such specimens can present with thoracic outlet syndrome and may have underlying systemic disorder. The present study is an attempt to show its morphological implications and clinical significance. 1 Postgraduate student 2 Professor & Head, corresponding author INTRODUCTION Presence of an extra rib, like a cervical rib, may cause nervous and vascular symptoms. Similarly the fusion of two ribs can also cause similar effects. Pressure on a nerve cause motor and sensory effects in the structures they supply (Williams and Warwick, ’80)). Bicipital rib is an unusual anatomical peculiarity which results due to fusion of shafts of two distinct ribs into a common body and is seen exclusively in relation to the first rib, either due to fusion of a cervical rib with first rib or more commonly due to fusion of first rib with the second (Turner, 1883; Terry and Trotter, ’53). Its incidence has been reported to be 0.3 per cent in a study based on chest radiographs (Gupta et al ., 2009). It has got many clinical implications. The present report is an attempt to explain its embryological basis, morphological implications and clinical significance. CASE AND OBSERVATION The present specimen was an incidental finding in the Dissection Hall, Department of Anatomy, Bangalore Medical College & Research Institute, Bangalore. The specimen was examined and relevant anatomical features and various measurements were observed. Morphometric analysis revealed fusion of left first and second ribs from a point 2.5 cm beyond the tubercle of upper rib obliteration first intercostal space except 3 cm anteriorly from first rib and 6 cm from second rib. The line of fusion was marked by a ridge extending from tubercle of first rib to middle of inner border of conjoint shaft. The length of the common shaft along the inner border measured 4 cm and presented as scalene tubercle. The length of the outer border measured 5 cm and had a tuberosity for scalenus anterior. The maximum width was 4 cm. The posterior part of internal surface of second rib had a costal groove (Fig. 1). DISCUSSION Fusion of sternal ends of ribs occurs in old age and is due to ossification spreading into and from costal cartilages. Fusion of vertebral ends of ribs occurs following lesions of intrathroacic contents, especially in long-standing collapse of lung. Fusion of middle third of first and second ribs is a rare condition.
Transcript of Synostosis of First and Second Ribs: A Case...
South Asian Anthropologist, 2015, 15(1): 15-17 New Series ©SERIALS 15
Synostosis of First and Second Ribs: A Case Report
VIDYA K. SHIVAKUMAR1 & PRIYA RANGANATH2
Department of Anatomy, Bangalore Medical College & Research Institute,Bangalore 560002, Karnataka
E-mail: [email protected]
KEYWORDS: Synostosis. Ribs. First and second. Clinical significance.
ABSTRACT: Partial fusion of ribs is a rare anatomical entity. Its incidence is reportedto be 0.3% in a study based on radiographs. In an incidental finding in the Dissection Hall,Department of Anatomy, Bangalore Medical College & Research Institute, Bangalore, therewas a specimen with partial fusion of left first and second ribs. Such specimens can presentwith thoracic outlet syndrome and may have underlying systemic disorder. The present study isan attempt to show its morphological implications and clinical significance.
1 Postgraduate student2 Professor & Head, corresponding author
INTRODUCTION
Presence of an extra rib, like a cervical rib, maycause nervous and vascular symptoms. Similarly thefusion of two ribs can also cause similar effects.Pressure on a nerve cause motor and sensory effectsin the structures they supply (Williams and Warwick,’80)).
Bicipital rib is an unusual anatomical peculiaritywhich results due to fusion of shafts of two distinctribs into a common body and is seen exclusively inrelation to the first rib, either due to fusion of a cervicalrib with first rib or more commonly due to fusion offirst rib with the second (Turner, 1883; Terry andTrotter, ’53). Its incidence has been reported to be0.3 per cent in a study based on chest radiographs(Gupta et al., 2009). It has got many clinicalimplications. The present report is an attempt toexplain its embryological basis, morphologicalimplications and clinical significance.
CASE AND OBSERVATION
The present specimen was an incidental findingin the Dissection Hall, Department of Anatomy,
Bangalore Medical College & Research Institute,Bangalore. The specimen was examined and relevantanatomical features and various measurements wereobserved.
Morphometric analysis revealed fusion of leftfirst and second ribs from a point 2.5 cm beyond thetubercle of upper rib obliteration first intercostal spaceexcept 3 cm anteriorly from first rib and 6 cm fromsecond rib. The line of fusion was marked by a ridgeextending from tubercle of first rib to middle of innerborder of conjoint shaft. The length of the commonshaft along the inner border measured 4 cm andpresented as scalene tubercle. The length of the outerborder measured 5 cm and had a tuberosity forscalenus anterior. The maximum width was 4 cm. Theposterior part of internal surface of second rib had acostal groove (Fig. 1).
DISCUSSION
Fusion of sternal ends of ribs occurs in old ageand is due to ossification spreading into and fromcostal cartilages. Fusion of vertebral ends of ribsoccurs following lesions of intrathroacic contents,especially in long-standing collapse of lung. Fusionof middle third of first and second ribs is a rarecondition.
16 Vidya K. Shivakumar & Priya Ranganath
Fig. 1: Synostosis of first and second ribs
Synostosis of First and Second Ribs 17
Rib anomalies have been traditionally classifiedinto numerical and structural (Rani et al., 2009).Numerical anomalies are common – supernumerary(cervical / lumbar) and deficient pair of eleventh ribs.Structural anomalies are rather rare and they can befurther classified into i) short ribs, ii) replacement ofcostal cartilage / part of rib shaft by fibrous tissue,iii) fused ribs. Fusion anomalies can be furtherclassified as bicipital, bifid or bridged varieties.
The ribs normally develop as extensions ofsclerotome tissue in the thoracic region (Arey, ’59).Irregular segmentation of primitive vertebral arhesleads to fusion anomalies. Recent experimental studiesin mice have implicated splotch gene mutations forvarious structural abnormalities in the ribs (Evans,2003).
In congenital anomalies of first rib, there ispostfixation of brachial plexus with a largecontribution from T2. As the shoulder girdle sagstraction affects the lower trunk causing neurologicalsymptoms (Plessis, ’75). There are at least 22 knownsyndromes in which fused ribs are a constantcomponent. Klippel Feil, Jarco Levin, Poland andGorlin syndrome are a few among them. Lastly fusedribs cause curvature of spine towards the area ofinvolvement causing an impediment both for normallung growth & respiration resulting in a conditionwhich has been aptly called thoracic insufficiencysyndrome (Leiwandrowski et al., nd.).
CONCLUSION
Bicipital rib can occur as an isolated anomalynot associated with other disease or may be a part ofa serious underlying disorder which has to be
thoroughly investigated. Variations is not only ofinterest to anatomists from academic point of viewbut is also of importance to radiologists & surgeonswho deal with this region as it has been implicated inthoracic inlet syndrome & a number of systemicdisorders. Fused r ibs may also restr ict theexpansion of chest wall which may require surgicalcorrection.
REFERENCES CITED
Arey, L. B. 1959. The skeletal system. In: Developmental Anatomy:A Textbook and Laboratory Manual of Embryology, 404-423. 6th edition. WB Saunders Company: Philadelphia &London.
Evans, D. J. R. 2003. Contribution of somatic cells to the avianribs. Developmental Biology, 256: 114-126.
Gupta, V., R. K. Suri, G. Rath and H. Loh H. 2009. Synostosis offirst & second ribs: anatomical & radiological assessment.International Journal of Anatomical Variations, 2: 131-133.
Leiwandrowski, K. U. et al., nd. Vertical rib expansion for thoracicinsufficiency syndrome: Indica tion & technique.www.orthojournalhms.org
Plessis, D. J. 1975. Bones. In: A Synopsis of Surgical Anatomy,224-250. 11th edition. John Wright & Sons Ltd. TheStonebridge Press: Bristol.
Rani, A., A. Rani, J. Chopra and P. Manik 2009. Synostosis offirst & second rib: A case report. Journal of AnatomicalSociety of India, 58(2): 189-191.
Terry, R. J. and M. Trotter 1953. The ribs. In: J. P. Schaeffer(ed.), Morris’ Anatomy: A Complete Systematic Treatise,pp. 192-198. 11th edition. The Blakiston Company: NewYork, Toronto.
Turner, W. M. 1883. Cervical ribs and the so called bicipital ribsin man in relation to corresponding structures in the Cetacea.Journal of Anatomy & Physiology, 17: 384-400.
Williams and Warwick 1980. In: Gray’s Anatomy, p. 292. 36th
edition. Churchill Livingstone: Edinburgh.
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